Printed circuits boards are generally the standard technology for forming complete electronic circuits by connecting different electronic components. Typically, batch processes of large numbers of boards produce the boards using photolithography steps. Circuits are formed of traces and laid down in layers, with vias and other interconnects connecting the various layers together.
This type of process has many difficulties in converting to a ‘produce-by-demand’ or custom manufacturing process. The reticles and patterns, as well as the photolithography equipment, are expensive and time-consuming to create and use. The process requires large manufacturing facilities. This all makes the typical large batch process more cost and time efficient.
Recently, Seiko Epson has demonstrated an ink jet printing process that results in an ultra-thin, multi-layer printed circuit board. Metal is printed in a nano-colloidal ink solution and then baked to remove the organic material. Insulators are also printed from solution. The ability to print multi-layer circuit boards has been demonstrated. Significant advantages exist in this process, including the ability to print a different circuit board every run, essentially production by demand with little or no change over or retooling costs.
Some limitations of the ink jet process include that the metal and insulator material must be able to be solution-processed. This constrains the materials set that one can use to print these boards. Typically, insulators that can be solution-processed have lower performance values than solid insulators. The same is true of solution-processed metals. They generally result in lower density lines, which may impact performance in connectivity and reliability.